/**
 * This file is part of pinyin4j (http://sourceforge.net/projects/pinyin4j/) and distributed under
 * GNU GENERAL PUBLIC LICENSE (GPL).
 * <p>
 * pinyin4j is free software; you can redistribute it and/or modify it under the terms of the GNU
 * General Public License as published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 * <p>
 * pinyin4j is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License along with pinyin4j.
 */

/**
 *
 */
package net.sourceforge.pinyin4j;

import com.hp.hpl.sparta.Document;
import com.hp.hpl.sparta.Element;
import com.hp.hpl.sparta.ParseException;

/**
 * Contains the logic translating among different Chinese Romanization systems
 *
 * @author Li Min (xmlerlimin@gmail.com)
 *
 */
class PinyinRomanizationTranslator {
    /**
     * convert the given unformatted Pinyin string from source Romanization
     * system to target Romanization system
     *
     * @param sourcePinyinStr
     *            the given unformatted Pinyin string
     * @param sourcePinyinSystem
     *            the Romanization system which is currently used by the given
     *            unformatted Pinyin string
     * @param targetPinyinSystem
     *            the Romanization system that should be converted to
     * @return unformatted Pinyin string in target Romanization system; null if
     *         error happens
     */
    static String convertRomanizationSystem(String sourcePinyinStr,
                                            PinyinRomanizationType sourcePinyinSystem, PinyinRomanizationType targetPinyinSystem) {
        String pinyinString = TextHelper.extractPinyinString(sourcePinyinStr);
        String toneNumberStr = TextHelper.extractToneNumber(sourcePinyinStr);

        // return value
        String targetPinyinStr = null;
        try {
            // find the node of source Pinyin system
            String xpathQuery1 =
                    "//" + sourcePinyinSystem.getTagName() + "[text()='" + pinyinString + "']";

            Document pinyinMappingDoc = PinyinRomanizationResource.getInstance().getPinyinMappingDoc();

            Element hanyuNode = pinyinMappingDoc.xpathSelectElement(xpathQuery1);

            if (null != hanyuNode) {
                // find the node of target Pinyin system
                String xpathQuery2 = "../" + targetPinyinSystem.getTagName() + "/text()";
                String targetPinyinStrWithoutToneNumber = hanyuNode.xpathSelectString(xpathQuery2);

                targetPinyinStr = targetPinyinStrWithoutToneNumber + toneNumberStr;
            }
        } catch (ParseException e) {
            e.printStackTrace();
        }

        return targetPinyinStr;
    }
}
